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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON |
ERFC(3) Linux Programmer's Manual ERFC(3)
erfc, erfcf, erfcl - complementary error function
#include <math.h>
double erfc(double x);
float erfcf(float x);
long double erfcl(long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
erfc():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
erfcf(), erfcl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
These functions return the complementary error function of x, that
is, 1.0 - erf(x).
On success, these functions return the complementary error function
of x, a value in the range [0,2].
If x is a NaN, a NaN is returned.
If x is +0 or -0, 1 is returned.
If x is positive infinity, +0 is returned.
If x is negative infinity, +2 is returned.
If the function result underflows and produces an unrepresentable
value, the return value is 0.0.
If the function result underflows but produces a representable (i.e.,
subnormal) value, that value is returned, and a range error occurs.
See math_error(7) for information on how to determine whether an
error has occurred when calling these functions.
The following errors can occur:
Range error: result underflow (result is subnormal)
An underflow floating-point exception (FE_UNDERFLOW) is
raised.
These functions do not set errno.
For an explanation of the terms used in this section, see
attributes(7).
┌─────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├─────────────────────────┼───────────────┼─────────┤
│erfc(), erfcf(), erfcl() │ Thread safety │ MT-Safe │
└─────────────────────────┴───────────────┴─────────┘
C99, POSIX.1-2001, POSIX.1-2008.
The variant returning double also conforms to SVr4, 4.3BSD.
The erfc(), erfcf(), and erfcl() functions are provided to avoid the
loss accuracy that would occur for the calculation 1-erf(x) for large
values of x (for which the value of erf(x) approaches 1).
cerf(3), erf(3), exp(3)
This page is part of release 4.12 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
GNU 2016-03-15 ERFC(3)
Pages that refer to this page: erf(3)